strncasecmp in strings.h?

[Karl Berry]

I received a bug report for Texinfo (about AIX 4.3.3) that strncasecmp
was not declared without #include <strings.h> -- that is, strings.h, not
string.h.

The spec at 
http://www.opengroup.org/onlinepubs/009695399/functions/strcasecmp.html
says the same.

The strcase gnulib module only mentions string.h, though, and we don't
seem to do anything with strings.h anywhere.
http://www.gnu.org/software/gnulib/MODULES.html#module=strcase

I don't know the best thing to do.  For my purposes, I guess I can
switch to c-strcase (or mbs*), but it seems like a bug somewhere ...

Thanks,
karl